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August rainfall records smashed as Isaac finally departs

1 PM UPDATE: Isaac finally reached Category 1 hurricane status in the northern Gulf of Mexico with winds of 75 mph. The storm was moving northwest at 10 mph and was expected to make landfall in southeastern Louisiana early Wednesday morning.

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ORIGINAL POST: Coastal Palm Beach County is set to shatter the all-time August rainfall record after a 9.03-inch three-day deluge from Tropical Storm Isaac.

If you add Friday’s 1.99-lashing to the Saturday-Monday total, 11.02 inches have fallen at Palm Beach International Airport over the four-day period.

That brings the August total to 22.28 inches at PBIA, easily washing away the old 20.12-inch record on the books at the National Weather Service, set in August 1995. Record keeping began in 1888.

Sunday’s official total of 5.52 inches broke the previous one-day record for the date set in 1949, according to the NWS in Miami.

The storm total includes 3.51 inches of rain that fell at PBIA on Monday, as far-flung rain bands from Isaac trained up Florida’s East Coast. In addition, the airport reported a wind gust of 61 mph, the strongest official reading of the four-day Isaac visit.

A flood watch was extended to 8 p.m. Tuesday in Palm Beach County with more rain expected on top of already saturated ground.

NWS analysts said 8-13 inches of rain have fallen over parts of the county since Sunday, and Doppler Radar estimates show that up to 20 inches may have fallen in some locations. Lesser amounts were reported in Broward and Miami-Dade counties.

At about 12 hours from landfall in southeastern Louisiana, Tropical Storm Isaac still hadn’t reached Category 1 hurricane status. But forecasters at the National Hurricane Center warned of dangerous storm surge associated with the system due to Isaac’s massive size.

The storm is so big, NWS forecasters in Miami said Palm Beach could still get an outer band from Isaac on Tuesday. Precipitation chances remained at 50 percent, but will drop to 20 percent on Wednesday under mostly sunny skies.